Noninvasive hemodynamic analyzer alterable to a continuous invasive hemodynamic monitor

ABSTRACT

A noninvasive method for calculating Actual Stroke Volume and Cardiac Output of a human heart uses computerized algorithms, and is implemented in a continuous noninvasive hemodynamic analyzer which computes a complete real-time Hemodynamic Profile with 12 parameters, in both rest and exercise modes. Inputs are received noninvasively by the analyzer, and a cascade of algorithms are used to calculate Stroke Volume, Ejection Fraction and Acceleration Index in Rest and Exercise. The analyzer displays or prints a summary in graphical form.

This application is a continuation of U.S. patent application Ser. No.08/314,732 filed Oct. 3, 1994 now abandoned, which is acontinuation-in-part Ser. No. of U.S. patent application Ser. No.08/140,453 filed Oct. 25, 1993, now U.S. Pat. No. 5,584,298.

BACKGROUND

1. Field of the Invention

This invention relates to a new noninvasive method for calculatingActual Stroke Volume and Cardiac Output of a human heart usingcomputerized algorithms, and to a continuous noninvasive hemodynamicanalyzer which computes a complete real-time Hemodynamic Profile in restand exercise.

2. Description of Prior Art

The principal role of Cardiac Output in the Hemodynamic Hierarchy hasresulted in a long felt need for an accurate measurement of blood flow.The fact is that if Cardiac Output is known, a whole sequence ofcardiovascular parameters can be calculated with the values of theeasily obtainable Blood Pressure Data. A noninvasive,continuous/frequently reapplicable, patient-, and user-friendly,inexpensive method could revolutionize modern health care by treatingpatients better at less expense.

There are about eight useful methods at the present time for measuringCardiac Output. The first three are the Fick Method, the Dye-IndicatorDilution Method, and the Thermodilution Method. Three other methodsallow visualization of the heart chambers; these includecine-angiography, gated-pool radionuclides, and echocardiography. Thetwo most practical noninvasive methods at the present time are DopplerUltrasound and Electrical Bioimpedance.

Although all these methods have some merit, there is no absolutelyaccurate method which could provide a standard to measure CardiacOutput. It is generally accepted in hemodynamic literature that allmethods have an inherent inaccuracy of ±10% and their absolute accuracyat best is ±15-20%. Therefore, if any two methods are compared to eachother, at least 75% of the points should fall within a ±20% confidenceband to establish good correlation.

A problem in the field of Cardiac Output-Measurement is that none of themethods fulfills all ideal requirements. In the following an attempt ismade to summarize the ideal requirements on a 100 point scale. Thedifferent categories are arbitrarily assigned the same weight for thesake of comparability.

1. Maximum inherent inaccuracy ±10% and absolute accuracy at best ±20%(10 points).

2. General availability for any kind of patient, considering:

a) no size and/or weight limitation(s) (2 points)

b) no age limitation(s) (2 points)

c) no time limitation (continuous measurability) (2 points)

d) no place limitation(s) (portability of instrument) (2 points)

e) simplicity of instrumentation (minimal proprietary item(s)) (2points)

3. Economical, considering:

a) price for testing for patient (2 points)

b) price for instrumentation, e.g., buying price of instrument(s) (2points)

c) price for place, e.g., home, ambulatory or hospital, etc. (2 points)

d) price for time, e.g., duration of test for doctor or technician(s)work (2 points)

e) price for evaluation, e.g., assessment with graphical capability (2points)

4. Technical make-up, e.g., complication of procedure on the part ofexaminer or for the examinee (10 points)

5. No setting requirement, e.g., can be operated any place from field tohospital (10 points)

6. No patient risk from any point of procedure (10 points)

7. Availability in any health condition, e.g., post MI-Stress Testing orCardiac Bypass-Operation and manageability of testing procedure in anybody position, e.g. supine, standing or moving (10 points)

8. Instantaneous repeatability and/or continuous monitoring, e.g., undersurgical procedure, postoperative care, etc. (10 points)

9. Real-time recognition of the patient's hemodynamic profile, e.g.,instantaneous Computer Programming Capability (10 points)

10. Instantaneous availability and/or directions for therapeuticmanagement (10 points).

Prior art cardiac output measurement methods use direct or indirectalgorithms to make the displayed value as close to the actual cardiacoutput as possible.

The current clinical standard for invasive measurement of CardiacOutput, for example, implements the Stewart-Hamilton equation. Athermodilution computer calculates the different correction algorithms.Its inaccuracy, which can be ±20% from the actual cardiac output, isclinically acceptable and this method is used in spite of riskassociated with this invasive method, its high cost, its intermittentcapability of use and its other major inherent inconvenience, thepossibility of infection.

A need exists, therefore, for the continuing development of noninvasivemethodologies to measure cardiac output. Presently only two types ofnoninvasive methods are available for continuous application: theDoppler ultrasonography and electrical bioimpedance methods.

The theoretical basis for the Doppler ultrasonography (continuous wave)method is the Doppler effect. Sound waves undergo a frequency shift whenthe distance between the generator and the receiver is changing. Dopplerultrasonography (Ultracom) is a reliable noninvasive procedure for oneclinical setting and its accuracy is directly proportional to severaltechnical assumptions. At best, the absolute accuracy of presentcontinuous-wave Doppler ultrasonography systems is no better than ±45%of the actual cardiac output. The frequency of use is very limited andthe systems are hospital-based. Furthermore, the results obtained bythis method are user-dependent and the equipment requires a skilledoperator.

The theoretical basis of the electrical bioimpedance method is the factthat the electrical conductivity of the thorax is proportional to thethoracic fluid content. Its changes are the result of volumetric andvelocity variation of blood (the most electrically conductive substancein the body) in thoracic vessels. These measured variables, togetherwith the volume of intrathoracic tissue (estimated by differentalgorithms of the computer from height, weight, and sex of the patient),are the basis for calculation of Stroke Volume and Cardiac Output.

BoMed Medical Manufacturing, Ltd., Irvine, Calif. markets its NCCOM3instrument which uses an electrical bioimpedance methodology. BoMed'sNCCOM3 has its clinically verified algorithms for cardiac outputmeasurements within ±20% of the actual value in the majority ofmonitored patients. Compared to other methods, such as Dopplerultrasonography, this method has advantages; more user-friendliness,unlimited applicability and repeatability, increased accuracy and aboveall, it provides an estimate of volemic status and oxygen delivery.

However, these heretofore known methods have major shortcomings. Withregard to continuous-wave Doppler ultrasonography, the maximum inherentinaccuracy and/or the absolute accuracy is not appropriate; the systemis not patient or user-friendly, it is not a hands-off technique, thereis inadequate accuracy at different flow levels, usability is limited(e.g. requires sterile environment) and it is not economical.

With regard to electrical bioimpedance measurements, there are thefollowing shortcomings: Limited in-patient and user-friendly aspects;complicated technical make-up, e.g., physician's understanding ofalgorithms and their limitations; limited availability of the instrument(hospital setting); limited usability in some health conditions,concerning electrode-placements (proprietary items); inseparability ofpatient and instrument, e.g., the data obtained is inherently tied tothe function of the instrument and one cannot use literature sources toreproduce previous evaluations; and lack of economy.

The present invention overcomes the problems which currently exist inthe field of Cardiac Output measurement methods and is able to approachthe ideal requirements noted above, up to about 94%, in contrast withthe Doppler and bioimpedance techniques, which meet only about 50-70% ofthe ideal requirements. In particular, these methods are not able tomeet the following requirements:

1. Simplicity of instrumentation and/or no proprietary item(s)

2. Economy--price of each instrument is prohibitively high, therefore,patient's expenses are increased

3. Technical make-up--complication of procedure

4. Setting-requirement--mostly hospital setting

5. Maneuverability of testing procedure.

SUMMARY OF THE INVENTION

Accordingly, a primary object of the invention is to provide anoninvasive cardiac output analyzer which uses a new method andapparatus unknown in the prior art.

A further object of the invention is to provide a cardiac outputanalyzer which is based on a network of algorithms, but which usesgenerally available blood pressure (systolic and diastolic) and heartrate data, as well as height, weight, and sex of the patient, date ofbirth, and the present date. The only nonobligatory data is theHemoglobin level, but without it the algorithm calculates the OxygenDelivery Index with the average Hemoglobin value according to the sex ofthe patient.

A further object of the present invention is to provide an economicalapproach to cardiac output measurement that provides reliable accuracyunknown in the prior art.

Yet another object of the present invention is to provide a novelpatient and user-friendly device capable of real-time measurement of thepatient's hemodynamic profile in rest and exercise modes.

Still another object of the present invention is to provide a means forevaluating and/or screening a large number of people for cardiovascularconditions noninvasively in an ambulatory setting, e.g., for sportsmedicine, military recruitment, or commercial pilot testing.

A further object of the invention is to provide a novel unlimitedcontinuous digital and/or graphical display of a comprehensivecardiodynamic profile for intensive care units, cardiac, surgical andpostoperative units using an arterial line for continuously andinvasively obtaining systolic & diastolic blood pressure and heart ratereadings.

An additional object of the invention is to provide a device which, usedsimultaneously with electrocardiography, will significantly increase thespecificity and sensitivity of a treadmill stress test.

Another object of the invention is to provide a method and apparatus forcollecting hemodynamic data in any type of exercise without anyrestriction, which can be used conveniently for exercise testing of alarge number of people who cannot afford the conventional treadmillexercise test.

Still another object of the present invention is to provide aninvestigative method useful in the presence of stressful conditionswhich could affect the patient's cardiovascular system. In this case thepresent invention provides a very convenient method to investigatecertain psychosomatic stress-effects (such as hyperventilation, coldpressure, positional changes, etc.) on the patient's real-timehemodynamic constellation and by this technique a new and scientificallybased method of stress management can be obtained. This approach will bevery valuable to check a larger number of patients in actualwork-settings, e.g. occupational medicine, military, commercial pilots,and testing.

A further object of the present invention is to provide an educationaldevice for medical students and other health workers. With the help ofthe computer many hemodynamic constellations and/or individual changescan be studied, presented or reconstructed in a manner which is helpfulfor prognostic and/or therapeutic viewpoints of certain cardiovascularconditions.

The present invention provides a method for hemodynamic analysis and anautomatic computerized hemodynamic analyzer which produces a variety ofuseful diagnostic displays and calculations. The method is used tocalculate Actual Stroke Volume and Cardiac Output of a human heart, andis implemented in a continuous noninvasive hemodynamic analyzer whichcomputes a complete real-time Hemodynamic Profile with twelveparameters, in both rest and exercise modes. Inputs are receivednoninvasively by the analyzer, and a cascade of algorithms are used tocalculate Stroke Volume, Ejection Fraction and Acceleration Index inrest and exercise modes. The analyzer displays or prints a summary ingraphical form.

In accordance with the present invention it is possible to diagnose andtreat Hypertensive Disease on a hemodynamic basis, etiologically and notsymptomatologically. The method and apparatus of the invention makes itpossible to perform these tasks economically and without restriction,e.g., expenses, place, mobility, technical make-up, etc. Large numbersof patients can be evaluated in a relatively short time and with thegraphical-printout capability provided by the invention, patientfollow-up is easy and comprehensible.

The method may also decrease the use of the invasive Swan-Ganz catheter,which is associated with several important potential complications. TheNoninvasive Hemodynamic Analyzer is able to obtain data directly andcontinuously about the preload: Left Ventricular End Diastolic Volume,which is closely related to the Pulmonary "Wedge" Pressure.

The Noninvasive Hemodynamic Analyzer calculates VO₂ : Maximal OxygenConsumption and its derivatives: METs level during exercise. This methodmeasures these parameters directly from the Cardiac Output and computesfor graphical representation the Exercise Capacity in Percentage(Efficiency Ratio).

The primary advantage of the present invention over the prior art is thesimplicity of the method, which is also (as in the case of othernoninvasive approaches, namely Doppler and electrical bioimpedance)based on a network of algorithms--but using generally available systolicand diastolic blood pressure and heart rate data. The other obligatoryinputs are easily obtainable (height, weight, sex, date of birth, andthe present date). The only non-obligatory data is the hemoglobin level,but if this is not available the algorithm calculates the oxygendelivery index with the average hemoglobin value according to the sex ofthe patient.

Another primary feature that differentiates the present invention fromprevious noninvasive methods and devices is its mobility andmaneuverability. It has no setting requirement(s). It can be used in anysituation, position, or place, sterile or non-sterile.

A further feature that makes present invention very convenient is itseconomy. The price of the testing device (and thus the test) issignificantly less than the cost of the prior art devices.

Still another primary feature that differentiates the invention from theprior art is the generous graphical presentation produced by the system,which covers every aspect of any hemodynamic changes and makes theevaluation and/or follow-up of either ambulatory and/or surgicalpatients very comprehensible on the computer screen and/or in printedform, at the nursing station, during anesthesia & surgery, etc.

Further objects and advantages of my invention will become apparent tothose skilled in the art from consideration of the following descriptionwith reference given to the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagnostic graph produced by the present system, showing tenhemodynamic values for a resting-supine position. The graph provides ahemodynamic profile and the ten calculated values can be evaluatedaccording to differences from normal ranges and represented as Normal,Low, or High. By this arrangement an immediate diagnostic summary can beachieved.

FIG. 2 is a diagnostic graph similar to that of FIG. 1 but showing theten hemodynamic values measured in a resting-upright position.

FIG. 3 is a therapeutic indication graph produced by the present system,showing a plot of the Cardiac Index against the Mean Arterial Pressurevalues in the Resting-Supine and Upright positions. The graph alsocontains two calculated hemodynamic parameters: the Ideal SystemicVascular Resistance Indices (straight diagonal line) and the Ideal LeftCardiac Work Indices (curved diagonal line) with ±20% ranges. The upperline of the Systemic Vascular Resistance Index represents vasodilatationand its lower line depicts vasoconstriction. The upper and lower curvesof the Left Cardiac Work Index demonstrate increased or decreasedMyocardial Oxygen Consumption as related to the Mean Arterial Pressure.The Upright-Ideal CI/MAP value is calculated according to the age andsex of the patient. The actual values of the Supine/Upright CI/MAPpositions can be referred to the ideal value and according to theirplace on the graph, therapeutic correction can be made.

FIG. 4 is a diagnostic graph produced by the inventive system, showingthe correlation between Ideal Resting Heart Rate (in the range of 37-43%of the Maximal Heart Rate) and the Ideal Range of Stroke Index. FIG. 4gives information about the composition of the Cardiac Index. Forexample, if the Stroke Index is increased but a normal Cardiac Indexexists, the seemingly normal Cardiac Index is the result of thecompensatory product of the increased Heart Rate.

FIG. 5 is a diagnostic graph produced by the inventive system showingCardiac Index plotted against Hemoglobin content. Assuming 95% arterialO₂ Saturation, the curved lines represent the range of normal OxygenDelivery Index. This graph can be read easily to provide informationabout Oxygen Supply and Demand.

FIG. 6 is a diagnostic graph produced by the inventive system plottingthe Stroke Index against the End Diastolic Index. The resultant ratiocan be depicted at the right as the % Ejection Fraction, one of the mostimportant indices of the Left Ventricle Efficiency.

FIG. 7 is a diagnostic graph produced by the present invention showingHemodynamic Reactivities for position changes from supine to upright.Cold pressure test and hyperventilation are represented by the groups ofchanges (changes are expressed in percentage of the average normalvalues) such as:

1. Mean Arterial Pressure, Stroke Index, Heart Rate, and SystemicVascular Resistance; and

2. End Diastolic Index as Preload, Cardiac Index & Acceleration Index asMyocardial Contractility and Systemic Vascular Resistance as Afterload.

FIG. 8 is a diagnostic graph produced by the present invention, similarto FIG. 7, showing hemodynamic reactivities during psychosomatic stressstimuli for Preload (EDI), Myocardial Contractility (CI & ACI) andAfterload (SVRI).

FIG. 9 is a diagnostic graph produced by the present invention, showingactual and ideal blood pressure values (Systolic, -Diastolic-, and MeanArterial Pressure) plotted against the % Heart Rate. By this graphicrepresentation the trend of exercise responses can be easilydemonstrated by comparison to the Ideal Values of these parameters.

FIG. 10 is a diagnostic graph produced by the present invention, showingstroke index changes plotted against % Heart Rate changes during anexercise test. The normal testing % Heart Rate range and the CalculatedIdeal Stroke Index Values (with the Ideal Body Surface Area) areindicated. Actual Stroke Indices are represented with Actual BodySurface Area and with Ideal Body Surface Area. Information obtained thisway shows the exercise indicated Stroke Index changes in comparison tothe Heart Rate, as influenced by the Body Size and Blood Pressurechanges, to indicate the functional capacity of the left ventricle.

FIG. 11 is a composite graph showing hemodynamic changes duringExercise, which presents interactions among preload (as end diastolicindex), myocardial oxygen consumption (as Left Cardiac Work Index), andafterload (as systemic vascular resistance index). For comparison theIdeal Indices of these parameters are also provided.

FIG. 12 is a graph produced by the present invention depicting aStarling Law curve, represented by plotting stroke index (SI) valuesagainst myocardial contractility (Acceleration Index) changes during anexercise test. The normal heart exhibits an ascending curve, for themajor portion of the myocardial contractility changes. However, afailing heart may produce a flattening or descending curve direction.

FIG. 13 is a graph produced by the present invention showing leftventricular end diastolic pressure in relation to cardiac index at rest.Left ventricular end diastolic pressure (pulmonary "wedge" pressure) isplotted against the Cardiac Index. By this presentation it isimmediately possible to obtain the state of pulmonary volemia and theperipheral perfusion with hypo-iso-and-hyper-designation of eachprojected point in Supine and Upright positions.

FIG. 14 is a graph produced by the present invention showing oxygenconsumption by plotting MET against % Heart Rate changes duringexercise. The graph shows the actual METs in correlation to the idealMETs, and the resultant Efficiency Ratio in %.

FIG. 15 is a drawing showing the hemodynamic analyzer apparatus of thepresent invention.

FIG. 16 is a block schematic diagram of the hemodynamic analyzerapparatus of the present invention.

FIG. 17 is a schematic diagram of the operational procedures used by thepresent invention, showing the transition from inputs to intermediaryparameters to final parameters.

FIG. 18 is a digram showing the hemodynamic interactions of the maincardiovascular parameters produced by the present invention.

FIGS. 19a and 19b together constitute a flowchart of an algorithm forcomputing actual and ideal hemodynamic parameters according to thepresent invention.

FIG. 20 is a flowchart showing the operation of the present invention tocomputing hemodynamic profiles.

FIG. 21 is a scattergram providing a statistical comparison of theoutput of the present invention with the output of a Bomed electricalbioimpedance measurement device.

FIG. 22 is a table showing a statistical summary of the scattergram ofFIG. 21.

FIGS. 23a and 23b show the data collected for a sample patient in theresting (supine and upright) positions. FIG. 23c shows data collectedfor the sample patient during the exercise stress test.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention provides a method for hemodynamic analysis and anautomatic computerized hemodynamic analyzer which produces a variety ofuseful diagnostic displays and calculations.

First, the method of performing the calculations according to thepresent invention will be described in detail.

The invention applies two calculation cascades to obtain the actualstroke volume and the corresponding hemodynamic state of a particularadult patient.

Through the first step the ideal stroke volume and the correspondingideal hemodynamic pattern are calculated. In the second sleep the actualstroke volume is computed by a factor (adjustment constant) relative tothe corresponding ideal stroke volume.

To calculate the ideal stroke volume of a particular patient thefollowing physiological correlation is utilized:

a) The pressure rate product (systolic BP * HR/100) plotted against HRis a linear correlation.

b) The maximal average heart rate can be obtained by using RegressionCoefficients according to age and sex.

c) Normal heart rate in a resting state is assumed to be 40±3% of thecalculated maximal heart rate.

d) From the maximal ideal pressure rate product (sex dependent) theideal systolic blood pressure values can be calculated for any givenheart rate: ##EQU1## e) Considering that mean arterial blood pressure isthe geometric average of the pulse area between SBP and DBP (anapproximate triangle): MAP- (SBP-DBP)/3!+DBP. Therefore,

f) DBP=MAP- (SBP-MAP)/2!

g) Thus through steps a) through f) an ideal systolic and diastolicblood pressure curve can be computed according to the correspondingheart rate, as ideal dynamic parameters.

h) With the above obtained dynamic parameters and static parameters,such as patient's age, height, weight (ideal weight for height andframe), sex and hemoglobin content--an ideal stroke volume and thecorresponding ideal hemodynamic profile can be calculated by the seriesof equations given herein.

The calculation of stroke volume is based on a theoretical model ofpulse wave propagation. In the aorta and/or blood vessels themanifestation of systolic blood pressure as a pulse wave originates bythe constriction of the left ventricle (systole). Although the valuesare different at the aortic level, the resulting mean arterial pressureis practically the same at the cubital area where blood pressure ismeasured.

The true stroke volume (or cardiac output) can be measured only in theascending aorta. However, that part of the blood volume which createsthe pulse wave in the peripheral major vessels is synchronous in time(pulse rate) with the bolus of the stroke volume. The pulse wave is theresult of the oscillation of systolic and diastolic pressure and theirdifference at the largest expansion is equal to pulse pressure.Calculating the average pulse pressure ratio as (systolic bloodpressure-diastolic blood pressure) /(60/HR), we can take this resultempirically as the largest circumferential extension of the bloodvessel.

If we assume that the pulse pressure ratio (PP-R) is essentially thecircumferential change of pulse wave→2 r*Π, we can calculate the area,equal to r² *Π, therefore ##EQU2##

The goal in this case is to calculate the Pulse Wave Volume, so theapproximate propagated bolus size (blood volume increase) will be equalto ##EQU3##

Multiplying the above equation by a floating factor and taking thesquare root value, a so called ideal stroke volume is empiricallycalculated, as divided by the basal surface area→ideal stroke index.This assumption is based on an adjustment of systolic-diastolic andheart-rate values to the sex, weight, and age of individual patient(Ideal BP & HR values). The actual stroke index is calculated in thesame way but it is corrected by an adjustment constant, obtained as thedifference between the Ideal Preliminary and Adjusted cardiac indices.

More specifically, these ideal parameters are calculated as follows.Pulse Wave Volume is determined based on the Ideal Pulse Pressure RatioI-PP-R according to Equation 2 above. The Preliminary Ideal StrokeVolume (I-SV_(P)) is then calculated using equation 3a below, butwithout multiplying by adjustment constant L. The Preliminary IdealStroke Volume is converted to a value of Preliminary Ideal CardiacOutput (I-CO_(P)) by multiplication with the Ideal Minimum Heart Rate(designated as 40% of the Ideal Maximum Heart Rate). The PreliminaryIdeal Cardiac Output is then indexed by dividing by an Ideal BodySurface Area (I-BSA) to obtain a Preliminary Ideal Cardiac Index(I-CI_(P)). I-CIp is then adjusted according to age using the formula((70-age)*0.35/50))+3.5 to obtain the real Ideal Cardiac Index (I-CI).The difference between I-CI_(p) and I-CI is then used as an adjustmentconstant in calculating an actual cardiac index, actual cardiac output,actual stroke volume, and actual stroke index, in a manner which will beexplained in more detail below.

The present invention provides algorithms to calculate the followingparameters:

1. STROKE VOLUME (Eq. 3)

2. ACCELERATION INDEX (Eq. 4)

3. % EJECTION FRACTION (Eq. 5)

4. IDEAL PRESSURE RATE PRODUCT (Eq. 6)

5. IDEAL SYSTOLIC PRESSURE (Eq. 7)

6. IDEAL DIASTOLIC PRESSURE (Eq. 8)

7. IDEAL PULSE PRESSURE (Eq. 9)

8. IDEAL PULSE PRESSURE RATIO (Eq. 10)

9. IDEAL MAP (Eq. 11)

10. IDEAL LVEDP (Eq. 12)

11. IDEAL VO₂ /METs (Eq. 13)

These algorithms will now be disclosed in more detail, starting with thealgorithm used to calculate the stroke volume.

CALCULATION OF STROKE VOLUME

1. If Heart Rate is >or=40% of Maximum Heart Rate: ##EQU4## A=PULSEPRESSURE RATIO-Actual: Pulse Pressure-Actual/(60/Heart Rate-Actual)

B=Heart Rate Ratio-Actual in msec!=60/Heart Rate-Actual

C=Floating Factor=((100-% Heart Rate-Actual)*E)+F

D=Heart Rate-Actual

E=Correction Factor 1=(1/K-1/G)/60

F=Correction Factor 2=1/G ##EQU5## where BSA-I is the ideal body surfacearea in m². H=If Age<=70 then ((70-Age)*I)+J else

If Age>70 then J

I=If Sex=M then 0.08

If Sex=F then 0.07

J=If Sex=M then 4

If Sex=F then 3.5 ##EQU6## L=Adjustment Constant=PreliminaryCI-Ideal-Adjusted CI-Ideal 2. If Heart Rate is <40% of Maximum HeartRate:

    (Eq. 1/Heart Rate-Actual)*(Heart Rate-Ideal Maximum-Heart Rate-Actual)+Eq. 1(Eq. 3b)

CALCULATION OF ACCELERATION INDEX (ACI)

The acceleration index (ACI) expresses the initial speed of ejectedblood from the left ventricle in the first 20 milliseconds before thestate of peripheral vessels can interfere. The ACI parameter closelyrepresents the true myocardial contractility. ##EQU7## where X is 1/1for a male subject and 1/3 for a female subject.

CALCULATION OF EJECTION FRACTION (EF)

In the first step an Ideal EF is calculated and adjusted to Heart Rate:

EF_(Ideal) =((% Heart Rate-Actual-40)*0.1)+57%

HR-Actual=HR*100/Max HR

57=Theoretical Average of EF

In the second step the Actual EF is calculated: ##EQU8##

The calculation of the ideal pressure rate product will now be explainedin detail.

CALCULATION OF IDEAL PRESSURE RATE PRODUCT (PRP-I)

    If Actual %HR<40 then PRP-I=A-((40-Actual% HR)*G)

    If Actual %HR>40 then PRP-I=((Actual %HR-40)*G+A)

    If Actual %HR=40 then PRP-I=A                              (Eq. 6)

where:

A=((B*C)*((D*40)/100))/100)→Minimum Ideal PRP

B=If Age<=20 then B=105

If Age>50 then B=140 → Minimum Ideal Systolic BP

Else B=((Age-20)*C)+105

C=(140-105)/30

D=If Sex=M then D=227-(1.032*Age)→Maximum Heart Rate

If Sex=F then D=206-(0.597*Age)

E=(D*40)/100→Minimum Heart Rate at 40% of Maximum Heart Rate

F=(100-40)→Maximum Range of Ideal % HR

G=F/60

CALCULATION OF IDEAL SYSTOLIC BLOOD PRESSURE (SBP-I)

    SBP-Ideal=(Pressure Rate Product-Ideal*100)/Heart Rate     (Eq. 7)

CALCULATION OF IDEAL DIASTOLIC BLOOD PRESSURE (DBP-I)

    DBP-Ideal=Mean Arterial Pressure-Ideal-((Systolic Blood Pressure-Ideal-Mean Arterial Pressure-Ideal)/2                                (Eq. 8)

CALCULATION OF IDEAL PULSE PRESSURE (PP-I)

    PP-Ideal=Systolic Blood Pressure-Ideal-Diastolic Pressure Ideal both at the same Heart Rate-Ideal                                     (Eq. 9)

CALCULATION OF IDEAL PULSE PRESSURE RATIO (PP-R-I)

    PP-R-I=PP-IDEAL/(60/HR)                                    (Eq. 10)

CALCULATION OF IDEAL MEAN ARTERIAL PRESSURE (MAP-I)

    MAP-I=(Age-20)*0.46+A                                      (Eq. 11)

where A=81 for females and 84 for males.

CALCULATION OF IDEAL LEFT VENTRICULAR END DIASTOLIC PRESSURE

    LVEDP=(30.16*log10(End Diastolic Index)))-log10(44))       (Eq. 12)

CALCULATION OF IDEAL OXYGEN CONSUMPTION/METs

    VO.sub.2 =((((1.5/60)*(60-(100-%HR))+4)*CO*10)/LBW         (Eq. 13)

METs=VO₂ /3.5

Using these calculated parameters, it is possible to calculate the wholehemodynamic spectrum with equations available in the hemodynamicliterature, in the following manner.

All measured and calculated parameters related to blood flow, such ascardiac output, are body mass dependent and their values cannot be usedto assess the adequacy of oxygen transport or pump performance. However,when these parameters are normalized by the patient's Body Surface Area(BSA), the resulting indexed values, such as cardiac index, then becomebody mass independent. Only indexed parameters should be used forclinical processing of patient data.

BODY SURFACE AREA (BSA) is calculated by the Du Bois formula

    BSA in square meters=weight kg!.sup.0.425 ×height cm!.sup.0.725 ×0.007184

    ______________________________________                                        Male: ((235-55)*(Height in inch - 48)/(84-48)) + 55                           Female: ((225-45)*(Height in inch - 48)/(84-48)) + 45                         According to Frame:                                                                           Small         90%                                                             Small/Medium  95%                                                             Medium Ideal BW:                                                                           100%                                                             Medium/Large 105%                                                             Large        110%                                             ______________________________________                                    

LEAN BODY MASS

Male: (IBW in lbs*100/115)/2.2046 in kg!

Female: (IBW in lbs*100/125)/2.2046 in kg!.

The following parameters are used for hemodynamic analysis in thepresent invention and the invention provides and uses these algorithms:

1. Stroke Index (SI): SI is the ejected blood volume from the leftventricle during systole and calculated as:

Eqs. 3a and 3b: Stroke Volume/Body Surface Area

Normal Range of Stroke Index (resting-supine adults): 35-65 ml/m²

2. Cardiac Index (CI): Global Blood Flow represented by CI--the mostimportant Oxygen-Transport-related parameter which is the indexedCardiac Output L/min/m² !.

CI=CO/BSA where CO is Cardiac Output in L/min.

Normal Range of Cardiac Index (resting-supine adults): 2.8-4.2 1/min/m²

3. AFTERLOAD: Systemic Vascular Resistance Index (SVRI) dyn.sec.cm⁻⁵ m²!

The ratio of Mean Arterial Blood Pressure to Mean Arterial Blood Flow isa measure of the resistance created by the blood vessel's contractilitystate. ##EQU9## where SVRI is the Systemic Vascular Resistance Index,LVEDP is Left Ventrical End Diastolic Pressure, and (MAP-LVEDP) is thearterio-venous pressure difference.

Normal Range of SVRI (resting-supine adults): 1660-2580 dyn.sec.cm⁻⁵.m²

4. % Maximum Heart Rate=Chronotropy: Maximal Heart Rate is calculated bythe regression coefficients devised by K. F. Hossack et al.:

For man=227-1.032 times Age

For woman=206-0.597 times Age

In several graphic representations it is convenient to expressChronotropy as %HR (HR*100/Max HR) for appropriate comparison ofdifferent individuals' hemodynamic changes. Normal health/male andfemale in rest have 40% of the Maximal Heart Rate.

5. Ejection Fraction (EF): Eq. 5

The pumping efficiency of the heart is represented by the EjectionFraction (EF). More specifically, EF represents the percentage of bloodvolume ejected from the left ventricle during systole.

EF Ranges:

High 65-80

Normal 50-65

Low 35-50

Poor 20-35

6. End-Diastolic Index (EDI)=PRELOAD

EDI is a measure of Preload, and is calculated as follows:

    EDI =SI/EF

EDI is a representative value for the systemic volemic state. NormalEnd-Diastolic Index (relaxing-supine adults): 60-110 ml/m²

7. Acceleration Index (Eq. 4)

ACI is the calculation of the initial speed of the aortic blood flow inthe first 20 milliseconds after the opening of the aortic valve at thebeginning of the systole. Because at this time other factors (such assystemic peripheral resistance) do not influence this initial speed ofblood flow, this acceleration closely reflects the true inotropic stateof the left myocardium.

Accepted normal ranges for males are 0.7-1.5 sec⁻², and for females, are0.9-1.7 sec⁻².

8. Left Cardiac Work Index (LCWI):

LCWI represents the physical work the left ventricle has to expend andis proportional to the myocardial VO₂ (Oxygen Consumption).

    LCWI=(MAP-LVEDP)*CI*0.0144

where

LCWI is Left Cardiac Work Index kg.m/m² !

LVEDP is Left Ventricular End Diastolic Pressure

(MAP-LVEDP) is pump's pressure contribution

0.0144 is a constant of proportionality.

Normal Left Cardiac Work Index (resting-supine adults): 3.3-5.3 Kg. m/m²

9. Oxygen Delivery Index (DO₂ I)

DO₂ I is the Global Oxygen delivered according to the Hemoglobin contentin the amount of blood of the indexed global flow, calculated as:

    DO.sub.2 I=CI×CaO.sub.2

where DO₂ I is Global Oxygen Delivery Index ml/min/m² !, CI is theCardiac Index, CaO₂ = Hemoglobin!×SaO₂ *1.34 (Hemoglobin in mg/liter),SaO₂ is the Arterial Oxygen Saturation level in %, 1.34 is a constant ofproportionality (ml Oxygen/gram of Hemoglobin). SaO₂ fluctuates in anarrow range (from 94-98%) if the patient has a healthy lung function,therefore, for purposes of the calculation, it can be consideredconstant, similarly to Hemoglobin. The only real variable in thisequation, reflecting changes in Oxygen delivery in the equation, is theCardiac Output. Normal DO₂ I (for resting-supine adults) is 570-795 O₂ml/min/m² for males and 480-670 O₂ ml/min/m² for females.

10. Mean Arterial Blood Pressure (MAP):

To maintain a physiologically optimal oxygenated Blood supply for thevital organs, such as the brain and the heart, a constant opening bloodpressure MAP is required, and this pressure is maintained by a cascadeof very sophisticated biofeedbacks. MAP is estimated as Diastolic BloodPressure+1/3 Pulse Pressure.

Normal MAP: (Age and Sex dependent)

males: 84-100 mmHg

females: 81-97 mmHg

11. Left Ventricular End Diastolic Pressure (LVEDP) (Eq. 12)

LVEDP, also known as Left Ventricular Filling Pressure is analogous tothe Mean Pulmonary Capillary "Wedge" Pressure in the absence of MitralValve Disease or Pulmonary Hypertension. The Noninvasive HemodynamicAnalyzer directly computers the LVEDI. The corresponding LVEDP can becalculated by plotting the logarithmic value of LVEDI against the LVEDP.

Normal LVEDP: (age and sex dependent) between 4-12 mmHg

12. Maximal Oxygen Consumption (VO₂) (Eq. 13)

This parameter represents the functional limits of the cardiopulmonarysystem and equals the product of CO*(a-vO₂). Since the maximal a-vO₂difference behaves as a constant and CO is calculated by the NoninvasiveHemodynamic Analyzer, an estimate of VO₂ can be continuously computed byusing the approximate difference of 1.5 a-vO₂ vol % for the equationbetween Rest (˜40% Max HR) and 100% Heart Rate (+the average restingvalue a-vO₂). VO₂ is also frequently expressed in METs. MET represents3.5 ml of O₂ /kg/min, which is about the amount of Oxygen required inresting state.

Referring to FIG. 15, an embodiment of the hemodynamic analyzeraccording to the present invention is shown. The apparatus includes amicrocomputer--capable of handling all algorithmic computationsresulting in a complete hemodynamic profile digitally and in graphicform. The results are displayed on an LCD Screen, or are printed out.The computer has a screen 1 and keyboard 5. The analyzer also includesarrhythmia light 2, pulse wave monitor 3, data input 4 (SBP-DBP & HR),heart rate panel 6, % heart rate panel 7, continuous heart rate input 8,and on/off switch 9.

The hemodynamic analyzer analyzes static and dynamic parameters aspatient's data and variable hemodynamic inputs, and computes hemodynamicparameters with digital and graphic output, including a hardcopyprintout. The apparatus preferably includes an oscillometric bloodpressure instrument, featuring an internal compressor that automatescuff inflation. Test sequelae are incorporated into computer-basedprocedure to obtain systolic & diastolic blood pressure and heart rate.The apparatus also includes a heart rate detector (an automaticarrhythmia selector) for missed beats, premature ventricularcontraction, etc., and three monitoring setups: a separateelectroluminescent display for visualization of pulse pattern, andcontinuous displays for actual heart rate and % heart rate.

Optionally, an arterial oxygen saturation monitor is included to providean exact calculation for the oxygen delivery index, which is importantduring a major operative procedure and/or when patient does not havenormal pulmonary function.

Significantly, the apparatus can be changed to an invasive apparatus byapplying an arterial pressure transducer, thus producing a continuous,on-line hemodynamic analyzer.

The programs operating in the microcomputer may include three differentprograms which run instantaneously according to the input data. Thefirst two programs are resting state programs, performing calculationsfor supine and upright positions, respectively, for diagnosing andtreating hypertension, congestive heart failure and other hemodynamiccompromised states.

The resting state programs preferably produce graphs for elucidatinginteractions/interconnections of a hemodynamic profile. The graphs mayinclude diagnostic directions of the hemodynamic analysis--supineposition (see Example); diagnostic directions of the hemodynamicanalysis--upright position (see Example); hemodynamic profile inresting--supine position (FIG. 1); hemodynamic profile inresting--upright position (FIG. 2); therapeutic indication: representingthe ideal and actual plotted points of cardiac index (CI) & meanarterial blood pressure (MAP) with calculations of left cardiac workindex (LCWI) & systemic vascular resistance index (SVRI) (FIG. 3);correlation between stroke index (SI) and heart rate in connection tocardiac index (CI) (FIG. 4); oxygen supply and demand in resting--supineand upright positions (FIG. 5); cardiac efficiency (%EF) in resting by amodified Starling Curve: stroke index (SI) is plotted against enddiastolic index (EDI) (FIG. 6); psychosomatic stress test: representinghemodynamic reactivities after applying cold stress and hyperventilationand graphically illustrating hemodynamic changes; mean arterial pressure(MAP), stroke index (SI), % heart rate, systemic vascular resistanceindex (SVRI) (FIG. 7); and preload (EDI), cardiac index CI), myocardialcontractility (ACI) and afterload (SVRI) (FIG. 8).

A third program performs calculations for an exercise stress test,representing detailed hemodynamic interactions using the followinggraphs: ideal and actual blood pressure (SBP, MAP & DBP) responses withthe corresponding % heart rate changes (FIG. 9); correlation between SIand % of the maximum heart rate during exercise (FIG. 10); compositegraph of hemodynamic changes during exercises, participating LCWI, SVRI,according to myocardial contractility (ACI) changes (FIG. 11); cardiacefficiency (%EF) changes during exercise as a manifestation of EDIchanges resulting in SI responses (FIG. 6); and a Starling Curve duringexercise comparing responses of SI to myocardial contractility changes.(FIG. 12).

Referring again to FIG. 15, after obtaining a continuous regular HeartRate pattern, operation begins after typing 9 obligatory and 2 optionaldata for single or multiple measurements. SBP, DBP & HR data arecollected automatically whenever the test procedure requires theregistration. SBP, DBP and HR can be typed in if desired. If an exercisestudy is performed, % Heart rate panel 7 helps to select the appropriateexercise level at about 40, 60 and 80% Heart Rates. An exercise studycan be performed if arrhythmia is not present.

The age of the patient is used by the algorithm and in the embodimentdisclosed, is restricted to ages 18-70.

The absolute limitation of any cardiac output measurement is heart rateirregularity. In the present invention--three regular electrodes areapplied on the chest and the hemodynamic analyzer by the pulse wavemonitor which continuously validates the ongoing test.

The computer algorithms used for computing ideal and actual hemodynamicparameters will now be described in detail with reference to FIGS. 19aand 19b. As illustrated in FIG. 19a and FIG. 19b the computer isprogrammed with two parallel algorithms 300 & 500 including an entryblock 302 wherein the program begins.

The algorithm begins operating only after the operator decides that nosignificant irregularities are present by judging the pulse pattern ofthe pulse wave monitor.

Thereafter, the program manually requests the block of staticcharacteristics 310 (including the patient's Name/Identification number,Date of test, Date of Birth, Sex, height (in inches), and weight (inlbs). When an interrupt occurs for Hemoglobin, actual Hemoglobin ifknown can be typed in or if is unknown, the average Hemoglobin will becomputed according to sex (M=15.3, F=12.9).

Thereafter, the algorithm enters block 330 of FIG. 19a: DynamicParameters, in which the computer inputs are provided either as a directdigital input from an automated blood pressure measuring system asdiscussed earlier, or indirectly as harvested information, manually. Theinputs provided are systolic blood pressure, diastolic blood pressure,and corresponding heart rate. After the computer receives both staticand dynamic parameters, two parallel cascades of algorithms will beinitiated.

In FIG. 19b, algorithms for computing the ideal Stroke volume and thecorresponding hemodynamic parameters are presented in five distinguishedblocks.

In the first process block in calculating ideal parameters, the heartrate values, such as ideal Maximal HR (block 502) and the ideal % HeartRates of Maximal Heart Rate, are calculated.

These calculations lead to the second process block of ideal PressureValues: ideal pressure rate products (block 512), ideal systolic bloodpressure (block 514), ideal mean arterial pressure (block 576), andideal diastolic blood pressure (block 518).

After these computations are fulfilled intermediary parameters of thethird process block are obtained: ideal heart rate ratios (block 522),ideal pulse pressure ratios (block 524), and ideal pulse pressure values(block 526) all at 40 to 100% of maximal heart rates.

In the fourth process block as described earlier with reference toEquations 3a and 3b, the ideal stroke volume calculation with its allassociated correction factors is presented. At this point ofcomputation, the adjustment(block 574), obtained (block 574), which isused in the parallel cascade of algorithm 300 for the actual strokevolume calculation in Equations 3a and 3b. In both parallel algorithms,ideal and actual, after obtaining the stroke volume levels, the twelvefinal hemodynamic parameters can be calculated by known, accepted,general physiological equations, with the exception of two parameters,namely: ideal and actual acceleration indices (Eq. 4), ideal and actual% ejection fractions (Eq. 5), and ideal and actual left ventricular enddiastolic pressure (Eq. 12) as described earlier. The last block offinal hemodynamic parameters consists of the following 12 hemodynamicparticipants: 380 and 550.

    ______________________________________                                        1.  MEAN ARTERIAL BLOOD PRESSURE                                                                              384                                           2.  CARDIAC INDEX               392                                           3.  END DIASTOLIC INDEX         396                                           4.  STROKE INDEX                372                                           5.  % EJECTION FRACTION         388                                           6.  ACCELERATION INDEX          386                                           7.  % HEART RATE OF MAX. HR     382                                           8.  SYSTEMIC VASCULAR RESISTANCE INDEX                                                                        394                                           9.  LEFT CARDIAC WORK INDEX     398                                           10. OXYGEN DELIVERY INDEX       400                                           11. LEFT VENTRICULAR END DIASTOLIC PRESSURE                                                                   402                                           12. MAXIMAL OXYGEN CONSUMPTION  404                                           ______________________________________                                    

FIG. 20 is a flowchart showing the operative steps to compute thehemodynamic profile in the present invention. As illustrated in FIG. 20,the operation starts placing the ECG electrodes on the chest (block 204)and blood pressure cuff preferably on the left arm (block 206) accordingto the pre-arrangement order (block 262). After static parameters aretyped in (block 208), the question: "Is arrhythmia present?" (block 210)will be answered. If answer is yes, computation will not start, andcontrol is transferred to exit the program (block 212).

If arrhythmia is not present, the first question, referring to one ofthe three test types--will be asked: "Is this a test in RESTING?" (block214). If the answer is yes, in block 218 the dynamic parameters,systolic and diastolic blood pressures and heart rate, will be receivedby computer 260 directly, as an analog computer input or manually bytyping.

If the next question is answered by yes: "Do you want a STRESS TEST?"(block 222) steps of Cold Stress Application (block 226),Hyperventilation (block 232) and Upright Position (block 242) will beinitiated by receiving their Dynamic Parameters in blocks 228, 234 and244.

After the yes answer of the next question: "Is this test an EXERCISEEVALUATION?" in block 238, two sets of Dynamic Parameters (blocks 250and 256) are collected preferably at 60 and 80% Heart Rate. By thissequence of steps three types of hemodynamic evaluation can be obtainedin block 300:

1. Hemodynamic Profile in Resting

2. Psychosomatic Stress Testing and

3. Exercise Stress Testing

with complete digital and graphic representations.

The apparatus of the present invention was used to monitor a young,healthy patient and determine his hemodynamic profiles, both in Restingand in an exercise stress test. The patient was exercising regularly andhad no cardiopulmonary history. The following information was obtained:

Static Parameters:

    ______________________________________                                        Name:                  D.L.                                                   ID No.:                2617                                                   Sex:                   Male                                                   Date of Birth:         6/12/57                                                Date of Examination:   03/20/93                                               Height:                71"                                                    Weight:                170 lbs                                                Hemoglobin:            15.3 g/dl                                              ______________________________________                                    

Dynamic Parameters:

    ______________________________________                                        Testing State                                                                              Rest               Exercise                                      Testing Type:                                                                              Supine  Cold      1st   2nd                                      ______________________________________                                        Systolic Blood                                                                             121     122        148  163                                      Pressure                                                                      Diastolic Blood                                                                            72      74         66   58                                       Pressure                                                                      Heart Rate   63      70         112  156                                      ______________________________________                                    

FIGS. 23a and 23b show the data collected for the patient in the resting(supine and upright) positions. FIG. 23c shows the data collected duringthe exercise stress test. The examples in FIGS. 1-6 and 13 are graphicalrepresentations of the collected resting data for this patient, whileFIGS. 9-12 and 14 graphically represent the stress test exercise datafor the patient.

An evaluation of the validity of the stroke volume/cardiac outputmeasurement of the present invention has been conducted. It is generallyrecognized that all invasive or noninvasive cardiac output methods havea biological error of measurement of 10-15%. Adding operator errors andinstrument calibration errors, the overall accuracy is never better than±20% from the actual cardiac output value.

The correct way, therefore, to assess the agreement between any twocardiac output methods is by using a scattergram and plotting +20%confidence band lines on it (because there is no existing calibrationstandard having absolute accuracy).

The method of the present invention was evaluated by calculating cardiacoutput of 50 men and women. For each person, four measurements wereobtained: measurements in supine and upright positions respectively(resting), and two measurements in an upright position during treadmillexercise. The data of 200 points were plotted against simultaneouslymeasurements obtained with the noninvasive bioimpedance method of theBoMed NCCOM3 instrument, as shown in FIG. 21.

An excellent correlation was obtained with 97% of the points scatteredbetween the ±20% Confidence Level Bands (88% between ±15% CLB and 75%between ±10% CLB), as shown by the analysis in FIG. 22.

Thus, the reader will see that the noninvasive hemodynamic sequentialanalysis of the present invention is a highly reliable and statisticallyproven method useful in calculating cardiovascular parameters includingcardiac output.

The present invention permits the user to compute a complete, real-timeHemodynamic Profile in Rest and Exercise. It provides the user with notonly a digital, but also an instantaneous graphical display with theability to print out hemodynamic changes. The invention also allows theuser a means to screen a large number of people for cardiovascularconditions in the most economical, fast and accurate way.

The invention also opens a new, direct approach for the medicalprofession to investigate and/or regulate hemodynamic changes followingdrug-therapy of different diseases and/or medical conditions (e.g.,Hypertension, Congestive Heart Failure, Postoperative Managements,etc.).

The inexpensive diagnostic, therapeutic and prognostic application ofthe present invention could significantly influence the economy ofmedical care to reduce the health care cost of these aspects.

Although the description above contains many specificities, these shouldnot be understood as limiting the scope of this Invention. What has beenshown are preferred embodiments of the present invention.

I claim:
 1. A computerized apparatus for electronically determiningcardiac parameters in a human patient in the presence of a regular heartrate pattern, comprising:computing means for receiving and storing a setof input parameters including a single actual heart rate value, a singleactual systolic blood pressure value and a single actual diastolic bloodpressure value, and sex, weight, age and height of the patient;calculating means associated with the computing means for generating anestimate of actual cardiac stroke volume from:(a) said single heart ratevalue, (b) blood pressure information consisting only of said singlesystolic and diastolic blood pressure values, and (c) said sex, weight,age, and height of the patient; and output means connected to thecalculating means for providing an output to an operator representingsaid estimate of actual cardiac stroke volume.
 2. The apparatus of claim1 further comprising monitoring means connected to the computing meansfor noninvasively obtaining said single actual heart rate value andsingle actual systolic and diastolic blood pressure values andtransmitting these values to the computing means.
 3. The apparatus ofclaim 1 further comprising display means connected to the calculatingmeans for generating a graphical hemodynamic profile output.
 4. Theapparatus of claim 3 wherein the calculating means further includesmeans for determining mean arterial blood pressure, cardiac index, enddiastolic index, stroke index, % ejection fraction, acceleration index,percent of maximum heart rate, systemic vascular resistance index, leftcardiac work index, and oxygen delivery index, and said display meansfurther includes means for providing the graphical hemodynamic profileoutput in the form of a bar graph showing mean arterial blood pressure,cardiac index, end diastolic index, stroke index, % ejection fraction,acceleration index, percent of maximum heart rate, systemic vascularresistance index, left cardiac work index, and oxygen delivery index. 5.The apparatus of claim 3 wherein the display means includes means forshowing a normal range for parameters displayed in the hemodynamicprofile.
 6. The apparatus of claim 1 wherein the calculating meansfurther includes:percent heart rate determining means for determining amaximum heart rate for the patient based on said input parameters andcalculating a % heart rate based on the actual heart rate and themaximum heart rate; ideal blood pressure determining means forcalculating an ideal systolic and an ideal diastolic blood pressure forthe patient at the % heart rate; preliminary ideal stroke volumedetermining means for calculating preliminary ideal stroke volume basedon the ideal systolic blood pressure and the ideal diastolic bloodpressure; preliminary ideal cardiac output determining means forcalculating a preliminary ideal cardial output value based on thepreliminary ideal stroke volume; indexing means for indexing saidpreliminary ideal cardiac output value to an ideal body surface area forthe patient to obtain a preliminary ideal cardiac index, and adjustingsaid preliminary ideal cardiac index according to patient age to obtainan ideal cardiac index; and actual cardiac stroke volume determiningmeans for estimating an actual cardiac stroke volume based on the actualheart rate, blood pressure, and the difference between the ideal cardiacindex and preliminary ideal cardiac index, and for providing saidestimated actual cardiac stroke volume to said output means.
 7. Theapparatus of claim 6 wherein the calculating means further includesmeans for determining whether the patient heart rate is less than 40% ofthe maximal heart rate, and if so, compensating for the decreased heartrate by correspondingly increasing the calculated value of the strokevolume.
 8. The apparatus of claim 1 further comprising means forcalculating a percent ejection fraction by a two step process whereininthe first step an Ideal ejection fraction is calculated and adjusted toheart rate according toEF_(ideal) =((%Heart Rate-Actual-40)*0.1)+57where %HR-Actual=HR*100/Max HR and 57 is the theoretical averageejection fraction; and in the second step the actual percent ejectionfraction is calculated according to: ##EQU10##
 9. The apparatus of claim1 wherein the calculating means further includes means for generating agraphical output relating at least two additional hemodynamicparameters, and further comprising display means for displaying saidgraphical output to facilitate diagnosis.
 10. The apparatus of claim 9wherein the display means further includes means for displaying an idealrelationship between said at least two hemodynamic parameters inaddition to a measured relationship.
 11. A computerized apparatus forelectronically determining cardiac parameters in a human patient in thepresence of a regular heart rate pattern, comprising:computing means forreceiving and storing a set of input parameters including a singleactual heart rate value, single actual systolic and diastolic bloodpressure values, and sex, weight, age and height of the patient, saidcomputing means further comprising means for receiving and storing ahemoglobin value; calculating means associated with the computing meansfor generating an estimate of actual cardiac stroke volume from saidsingle heart rate value, said single systolic and diastolic bloodpressure values, and said sex, weight, age, and height of the patient,wherein said estimate of actual cardiac stroke volume is calculatedbased only on said single heart rate value, said single systolic anddiastolic blood pressure values, said sex, weight, age, and height ofthe patient, and said hemoglobin value; and output means connected tothe calculating means for providing an output to an operatorrepresenting said estimate of actual cardiac stroke volume.
 12. Acomputer program for electronically determining cardiac parameters in ahuman patient in the presence of a regular heart rate pattern,comprising a recording medium encoded with computer program codes, saidcodes defining:computing means for receiving and storing a set of inputparameters including a single actual heart rate value, a single actualsystolic blood pressure value and a single actual diastolic bloodpressure value, and sex, weight, age and height of the patient;calculating means associated with the computing means for generating anestimate of actual cardiac stroke volume from:(a) said single heart ratevalue, (b) blood pressure information consisting only of said singlesystolic and diastolic blood pressure values, and (c) said sex, weight,age, and height of the patient; output means connected to thecalculating means for providing an output to an operator representingsaid estimate of actual cardiac stroke volume; and display meansassociated with the calculating means for receiving output therefrom andgenerating a graphical hemodynamic profile output.
 13. The computerprogram of claim 12 herein the computing means further comprises meansfor receiving and storing a hemoglobin value, wherein said estimate ofactual cardiac stroke volume is calculated based only on said singleheart rate value, said single systolic and diastolic blood pressurevalues, said sex, weight, age, and height of the patient, and saidhemoglobin value.
 14. The computer program of claim 12 wherein thecalculating means further includes:percent heart rate determining meansfor determining a maximum heart rate for the patient based on said inputparameters and calculating a % heart rate based on the actual heart rateand the maximum heart rate; ideal blood pressure determining means forcalculating an ideal systolic and an ideal diastolic blood pressure forthe patient at the % heart rate; preliminary ideal stroke volumedetermining means for calculating preliminary ideal stroke volume basedon the ideal systolic blood pressure and the ideal diastolic bloodpressure; preliminary ideal cardiac output determining means forcalculating a preliminary ideal cardial output value based on thepreliminary ideal stroke volume; indexing means for indexing saidpreliminary ideal cardiac output value to an ideal body surface area forthe patient to obtain a preliminary ideal cardiac index, and adjustingsaid preliminary ideal cardiac index according to patient age to obtainan ideal cardiac index; and actual cardiac stroke volume determiningmeans for estimating an actual cardiac stroke volume based on the actualheart rate, blood pressure, and the difference between the ideal cardiacindex and preliminary ideal cardiac index, and for providing saidestimated actual cardiac stroke volume to said output means.
 15. Thecomputer program of claim 14 wherein the calculating means furtherincludes means for determining whether the patient heart rate is lessthan 40% of the maximal heart rate, and if so, compensating for thedecreased heart rate by correspondingly increasing the calculated valueof the stroke volume.
 16. The computer program of claim 12 furthercomprising means for calculating a percent ejection fraction by a twostep process whereinin the first step an Ideal ejection fraction iscalculated and adjusted to heart rate according toEF_(Ideal) =((%HeartRate-Actual-40)*0.1)+57 where %HR-Actual=HR*100/Max HR and 57 is thetheoretical average ejection fraction; and in the second step the actualpercent ejection fraction is calculated according to: ##EQU11##